Had this happen on manual mill before my concrete slab was poured because different logs caused bed to flex. Even though it was level when nothing was on or running. (Check this first)

Also blade tensioner loosened once in my LT-10 (actually snapped) and after I realized that was there for a Very Important reason I check it each startup for tightness...no more wavy lines. I tried a bush fix with eye bolts and nuts, get the right tensioner from the factory; and keep one on backup.

And lastly what MM said, slow down to a crawl and cut once at a foot per 10sec rate and see if it comes out straight. This way you are taking the extra factors caused by “stress” out of the equation. Like letting a chainsaw cut without pushing, sharp blade should not go sideways if working correctly.

While it is interesting, none of this discussion about roller guide down pressure will help Jim identify his problem. I think we all agree that his saw should cut straight without any blade guides at all. So the problem must lie elsewhere. More to the point, I think that having Jim adjust his guides is an incorrect diagnosis for his problem.

As I work down my troubleshooting checklist, I think that Jim has verified that the blade is sharp and the wheels are in alignment, but I'm not sure that he has checked off the box next to "Proper blade tension". I know he addressed the blade tension, but I didn't get the impression that he had fully ruled this out as an issue. So increasing blade tension would be my next troubleshooting step. In fact, he should lubricate all of the blade tensioning equipment on his mill as this could simply be an issue of lack of lubrication.

After ensuring the blade tension is correct, I would check to make sure something isn't taking the set out of the blades. Originally the problem appeared after Jim had blades sharpened by a local guy. New blades cut fine (see his original post). At that time it appeared to be faulty sharpening/improper set.

Now he has the problem with a new set of rollers and new blades. The video of the wavy cut makes me think something is flattening the tooth set. Could be my inexperience with sawmills but my woodworking experience leads me this way.

If the blade loses its set on the inside (the side against the wheels) wouldn't it want to cut to the outside aka dive?

What does the sawdust between the cant and the board look like? Fine and loose or packed tight? Insufficient set would leave packed dust in the cut. I still think the dive belt is slipping, weather that be on the drive wheel or the blade itself slipping on the drive wheel. Does not the Norwood use the drive belt as the wheel belt as well? Change the belt.

Well, I tried the recommendations I got from Norwood support. One was to thaw out the cant and to try a brand new blade. So I put up a 12" poplar that has been in the sun all day. Soft wood, very much not-frozen. Brand new Cooks blade.

Here is a video of what I got.

Blades should run flat on the entire surface of the guide rollers. Pictures can be deceiving, but in your picture their is a shinny streak along the front of the roller the length of the blade. IMHO this would indicate the blade is not running flat on the roller and pitched at an angle is causing it to dive. In the dark, shine a light under the roller and see if it has full contact to the roller's full width or if it is indeed twisted or you can check with a "Blade Guide Alignment Tool". Again it may just be an illusion in the picture.

I m running a norwood with the same set up and had the same problem last summer. after discussing it with the guy the dose my sharping for me we found the problem. On a norwood mill the roller guides are just that "guides" they are not meant to hold the band. after checking everything we found the roller guides had worning down from front to back and where guiding the band down. after replacing the rollers it ran great for about 2 logs then same thing "diving". I discussed it again with the sharping guy he told me to "get the used band off the mill and try to coil it". BINGO it didn't coil up easily. turns out when it started to dive from the worn out rollers I would over come that problem by tighting up my bands more and by over tighting them. the bands lost some temper. the old bands would sharping and cut fine till the heated up the they would lose set. costly lesson learned. with the new rollers and all new bands it cuts straight as an arrow again.

check you roller guides with calipers they cant be more then 1/10000 out from front to back. I replace them every fall now. but im doing a ton of milling and use the bands for you self and when they start to dive. throw them awaynothing wrong with reshaping( i use bands till they done. usually 4 to 5 sharpings) but for whatever resin your bands have lost the temper in the steel and will never wok properly again.

and make sure the bands are running about 3/4 on the belts. if the teeth of the band are running to close to the belts it will also take the set out. and the backs of the roller guides should be a 1/4 inch from the back of the band

One item that I have not seen mentioned is buildup on the blade. In the video and also in the pictures on the previous page I am seeing some buildup. It has been cleaned off between the blade guides, but between the guides and bladewheel, I am seeing buildup.

Buildup on the blade will cause wavy cuts so one other item to address is blade lube/cleaner, or lack thereof.

One item that I have not seen mentioned is buildup on the blade. In the video and also in the pictures on the previous page I am seeing some buildup. It has been cleaned off between the blade guides, but between the guides and bladewheel, I am seeing buildup.Buildup on the blade will cause wavy cuts so one other item to address is blade lube/cleaner, or lack thereof.

MM has sharp eyes. At 1:10 in the video you can clearly see the buildup, shiny to the left of the blade guide, but just dark crap between the guides. This is the shiny streak that Remle noticed. It doesn't look like enough to affect the cut in softer woods but I wonder what the outside of the blade looks like.

Took a power washer to the mill and cleaned every bit of build up anywhere on the machine. But it made no difference in how the machine cut.

When I spoke to support at Norwood, they suggested some things, all of which I tried with no change in cut. Their final suggestion was to change back to the ceramic guides, which I did yesterday morning. It made a little bit of difference. I found that if I cut extremely slow, and I mean extremely slow, I can push the blade through the log with minimal waviness.

The product wouldn't be acceptable for sale; no way anyone would want to buy it. But I did at least get a few boards cut to finish a deck that I had been building. (Nothing makes me angrier than to have to buy lumber at Lowes because my mill can't produce what I need.)

So the ceramics made a little difference, but they aren't fixing the problem, just masked it a bit. What I have noticed though is that the three planks I cut yesterday have a washboard look to them. Saying "washboard" probably doesn't really describe the effect I'm seeing, it's more like the cutting edge, or teeth, on a file. I know it's an exaggeration, but if I could pick up the plank and flip it over, I could use it to file something.

I'm going to dismantle and reassemble the bed this weekend. May do the same with the carriage. Not sure what the next step will be if all this fails but given there is no Norwood support in my area I may be faced with a new purchase. There is a limit to every man's patience, and I've found mine.

Hate to sound like a broken record, but again I have to ask, is this only happening since you changed blade brands? Are the problems all from the same box of blades? I know you mentioned the resharpened blades were a problem too. Have you tried any of the other resharps? Have you tried any other batch of blades than these two? Have you tried changing or adjusting the tension of the drive belt? You don't have to see the belt slipping to be loosing blade speed. Can you hear the engine speed decrease as the blade begins to cut or does it remain the same in and out of the log? Years ago I had these same issues on a different brand mill and finally narrowed it down to a slipping drive belt. Couldn't see a thing. Belt was slipping ever so slightly at the engine pulley, just enough to loose blade speed. Tightening helped some but changing the belt solved the issue.

Hate to sound like a broken record, but again I have to ask, is this only happening since you changed blade brands? A: No, I have used Norwoods blades, resharpened Norwood blades and now brand new Cooks blades. Problem persists.

Are the problems all from the same box of blades? I know you mentioned the resharpened blades were a problem too. Have you tried any of the other resharps? A: No, blades have come from several sources.

Have you tried changing or adjusting the tension of the drive belt? A: Yes, I have adjusted the tension of the drive belt, I have dissasembled the bed and reassembled it. I have used both the roller guides and now I have put the ceramics back on.

Can you hear the engine speed decrease as the blade begins to cut or does it remain the same in and out of the log? A: No decrease in engine speed. Sound is consistant.

Years ago I had these same issues on a different brand mill and finally narrowed it down to a slipping drive belt. Couldn't see a thing. Belt was slipping ever so slightly at the engine pulley, just enough to loose blade speed. Tightening helped some but changing the belt solved the issue.

LeeB, I answered your questions in your quote as it was easier to address them individually.

I don't mind sounding like a broken record, you need to put 1/4" down pressure on those roller guide no matter what it takes. Without down pressure you may as well not use them. Steve

I have removed them, Steve. I am now working with the factory default ceramics. I see a little difference, but I think it's just that the ceramics are helping to camouflage the problem. I am now in the process of disassembling and reassembling the carriage. Hopefully, whatever it causing the problem will get fixed along the way. :-)

With roller guides you NEED 1/4 down pressure to work right. If ceramic guides are tight to the band with no wear they would control the blade good but tight to the band and no wear only happen when brand new and adjusted tight. Why do you spend time and money messing with the carriage rather than fixing the problem. I give up trying to help. Steve

I bought some cooks bands a box of ten They never made a good cut on my millWon't stay on the wheels and make wavy cuts.I not bashing cooks at all.But the box I got Don t work for me even when resharpebed.I have WM,Timber wolf,Ripper 37 and Kasco all cut great

Tonight I removed the rails from the bed and reinstalled them. They just didn’t feel right, even though the alignment tool that Norwood sends with the saw indicated everything was aligned correctly. Felt like the carriage was binding as I pushed it along. Not bad, but not real smooth like you would expect.

I put an aluminum 4’ level along the side of the rails, and it was obvious that there were inward and outward bows along the track. Not visible by looking at it and not picked up with the alignment tool, but they were there for sure.

I took a finish hammer and tapped them until the entire run on each side was perfect. Ran the carriage down the track and wow, what a difference. Not saying that was the entire problem, but I believe that was where the problem was starting.

Next, I re-adjusted the band-wheels so that the teeth of the bandsaw blade were about ˝” (perhaps a little more) away from the edge of the belt. The blade teeth were much closer to the belt previously. I reassembled the rest of the saw, put on and tightened a new cooks blade, filled the lubricant container, and fired it up.

The first cut was marvelous! So was the second, third and fourth. It’s dark now so that was all I could do tonight. But tomorrow I’ll toss on another log and see what happens.

But here is what I “think” has been happening, and yes, it was touched on earlier in this thread by GMM and Nomad both. I believe the (out of true) rails were binding the carriage as I pushed it, which caused the blade to push back against the rollers to the point that the back side of the blade rode up on the back of the roller. In this position, the blade would be pointing down and was forced to dive into the cut. As such, it would straighten up as soon as I slowed down on the cut and the blade got back into correct position.

But more importantly, with the blade being shoved back that far, the teeth were probably running against the band-wheel, compressing them into a configuration that wasn’t conducive to any kind of straight cut. Once the blade was damaged to this degree, it wasn’t ever going to cut correctly again, and wavy cuts were all it would ever produce from that point on. This would explain why the first cut with a new blade was always good and the following cuts were always crap.

So that’s where we are tonight. I’m closer to having this figured out than I’ve been in a very long time. The tricky part here was that there were so many small things contributing to the problem, and not one big thing.

So fingers crossed that the saw works as well tomorrow as it did tonight.

In retrospect, it was probably just the dirty water in the lubricant tank and the new water did the trick… J/K of course. :-)

Good to hear an update from you Jim! Your decision to go back to factory default ceramic guides is a good one. You want to eliminate all the variables so that you can focus on the real issue. To risk sounding like a broken record, "That saw should cut straight without any guides whatsoever!"

You did well by straightening your guide rails but that's not where your blade issue is. Your blade diving issue is in the carriage. I'm concerned with your wheel tracking adjustment which puts your teeth 1/2 " in front of your wheel. You are now in the area where you will begin throwing blades off of your mill. I'm not worried because when you throw your first blade you will correct the alignment immediately, (yes, it's that dramatic).

Jim, I'm wondering if you have tried to over tension your blade? I mean I want you to over tension the s*** out of your blade and see if it cuts straight. Best of luck, and we are eager for updates.